dbgcnt.def (ra_byte_scan): Added.

2008-04-24  Richard Sandiford  <rsandifo@nildram.co.uk>
	    Kenneth Zadeck <zadeck@naturalbridge.com>

	* dbgcnt.def (ra_byte_scan): Added.
	* dbgcnt.c (dbg_cnt): Added code to print message to dump_file
	when the last hit happens for a counter.  
	* timevar.def (TV_DF_BYTE_LR): New variable.
	* tree-pass.h (pass_fast_rtl_byte_dce): New pass.
	* passes.c (pass_fast_rtl_byte_dce): New pass.
	* fwprop.c (update_df): Added mode to call df_ref_create.
	Renamed DF_REF_WIDTH and DF_REF_OFFSET to DF_REF_EXTRACT_WIDTH and
	DF_REF_EXTRACT_OFFSET.
	* df.h (DF_BYTE_LR, DF_BYTE_LR_BB_INFO, DF_BYTE_LR_IN, 
	DF_BYTE_LR_OUT, df_byte_lr): New macro.
	(df_mm): New enum.
	(df_ref_extract): Added mode field.
	(DF_REF_WIDTH, DF_REF_OFFSET) Renamed to DF_REF_EXTRACT_WIDTH and
	DF_REF_EXTRACT_OFFSET.
	(DF_REF_EXTRACT_MODE): New macro.
	(df_byte_lr_bb_info): New structure.
	(df_print_byte_regset, df_compute_accessed_bytes, 
	df_byte_lr_add_problem, df_byte_lr_get_regno_start,
	df_byte_lr_get_regno_len, df_byte_lr_simulate_defs,
	df_byte_lr_simulate_uses,
	df_byte_lr_simulate_artificial_refs_at_top,
	df_byte_lr_simulate_artificial_refs_at_end,
	df_compute_accessed_bytes): New function.
	(df_ref_create): Add parameter.
	(df_byte_lr_get_bb_info): New inline function.
	* df-scan.c (df_ref_record, df_uses_record,
	df_ref_create_structure): Added mode parameter.
	(df_ref_create, df_notes_rescan, df_ref_record, df_def_record_1, 
	df_defs_record, df_uses_record, df_get_conditional_uses,
	df_get_call_refs, df_insn_refs_collect, df_bb_refs_collect, 
	df_entry_block_defs_collect, df_exit_block_uses_collect):
	Added mode parameter to calls to df_ref_record, df_uses_record,
	df_ref_create_structure.
       	(df_ref_equal_p, df_ref_compare): Added test for modes.
	(df_ref_create_structure): Added code to set mode.  Renamed
	DF_REF_WIDTH and DF_REF_OFFSET to DF_REF_EXTRACT_WIDTH and
	DF_REF_EXTRACT_OFFSET.
	* df-core.c (df_print_byte_regset): New function.
	* df-byte-scan.c: New file.
	* df-problems.c (df_rd_transfer_function): Removed unnecessary
	calls to BITMAP_FREE.  
	(df_byte_lr_problem_data, df_problem problem_BYTE_LR): New structure.
	(df_byte_lr_get_regno_start, df_byte_lr_get_regno_len,
	df_byte_lr_set_bb_info, df_byte_lr_free_bb_info, 
	df_byte_lr_check_regs, df_byte_lr_expand_bitmap, 
	df_byte_lr_alloc, df_byte_lr_reset, df_byte_lr_bb_local_compute,
	df_byte_lr_local_compute, df_byte_lr_init,
	df_byte_lr_confluence_0, df_byte_lr_confluence_n, 
	df_byte_lr_transfer_function, df_byte_lr_free, 
	df_byte_lr_top_dump, df_byte_lr_bottom_dump,
	df_byte_lr_add_problem, df_byte_lr_simulate_defs, 
	df_byte_lr_simulate_uses,
	df_byte_lr_simulate_artificial_refs_at_top,
	df_byte_lr_simulate_artificial_refs_at_end): New function.
	* dce.c (byte_dce_process_block): New function.
	(dce_process_block): au is now passed in rather than computed
	locally.  Changed loops that look at artificial defs to not look
	for conditional or partial ones, because there never are any.  
	(fast_dce): Now is able to drive byte_dce_process_block or 
	dce_process_block depending on the kind of dce being done.
	(rest_of_handle_fast_dce): Add parameter to fast_dce.
	(rest_of_handle_fast_byte_dce): New function.
	(rtl_opt_pass pass_fast_rtl_byte_dce): New pass.
	* Makefile.in (df-byte-scan.o, debugcnt.o): Added dependencies.




Co-Authored-By: Kenneth Zadeck <zadeck@naturalbridge.com>

From-SVN: r134523

1 files changed, 78 insertions, 0 deletions

diff --git a/gcc/dbgcnt.def b/gcc/dbgcnt.def
index b2382f1..7a59af3 100644
--- a/gcc/dbgcnt.def
+++ b/gcc/dbgcnt.def
@@ -61,6 +61,83 @@ along with GCC; see the file COPYING3.  If not see
    Use -fdbg-cnt=counter1:N,counter2:M,...
    which sets the limit for counter1 to N, and the limit for counter2 to M, etc.
    e.g. setting a limit to zero will make dbg_cnt () return false *always*.
+
+   The following shell file can then be used to binary search for
+   exact transformation that causes the bug.  A second shell script
+   should be written, say "tryTest", which exits with 1 if the
+   compiled program fails and exits with 0 if the program succeeds.
+   This shell script should take 1 parameter, the value to be passed
+   to set the counter of the compilation command in tryTest.  Then,
+   assuming that the following script is called binarySearch,
+   the command:
+
+	binarySearch tryTest 
+
+   will automatically find the highest value of the counter for which
+   the program fails.  If tryTest never fails, binarySearch will
+   produce unpredictable results as it will try to find an upper bound
+   that does not exist.
+
+   When dbgcnt does hits the limit, it writes a comment in the current
+   dump_file of the form:
+
+       ***dbgcnt: limit reached for %s.***
+	
+   Assuming that the dump file is logging the analysis/transformations
+   it is making, this pinpoints the exact position in the log file
+   where the problem transformation is being logged.
+
+=====================================
+#!/bin/bash
+
+while getopts "l:u:i:" opt
+do
+    case $opt in
+        l) lb="$OPTARG";;
+        u) ub="$OPTARG";;
+        i) init="$OPTARG";;
+        ?) usage; exit 3;;
+    esac
+done
+
+shift $(($OPTIND - 1))
+echo $@
+cmd=${1+"${@}"}
+
+lb=${lb:=0}
+init=${init:=100}
+
+$cmd $lb
+lb_val=$?
+if [ -z "$ub" ]; then
+    # find the upper bound
+    ub=$(($init + $lb))
+    true
+    while [ $? -eq $lb_val ]; do
+        ub=$(($ub * 10))
+        #ub=`expr $ub \* 10`
+        $cmd $ub
+    done
+fi
+
+echo command: $cmd
+
+true
+while [ `expr $ub - $lb` -gt 1 ]; do
+    try=$(($lb + ( $ub - $lb ) / 2))
+    $cmd $try
+    if [ $? -eq $lb_val ]; then
+        lb=$try
+    else
+        ub=$try
+    fi
+done
+
+echo lbound: $lb
+echo ubound: $ub
+
+=====================================
+
 */
 
 /* Debug counter definitions.  */
@@ -73,6 +150,7 @@ DEBUG_COUNTER (dce)
 DEBUG_COUNTER (dce_fast)
 DEBUG_COUNTER (dce_ud)
 DEBUG_COUNTER (delete_trivial_dead)
+DEBUG_COUNTER (df_byte_scan)
 DEBUG_COUNTER (dse)
 DEBUG_COUNTER (dse1)
 DEBUG_COUNTER (dse2)